Reinforced stitched seam for high-tensile woven fabrics

ABSTRACT

The invention concerns a stitched seam for high-tensile woven fabric sections, in particular dryer screen fabric for paper machine clothing, wherein the warp yarn loops ( 6 ) located at the end of the two woven fabric sections ( 1, 2 ) to be interconnected are interconnected at the common seam line by a closure wire ( 9 ). Associated with the warp yarn loops ( 6 ) at the location of the stitched seam and with the closure wire ( 9 ) is at least one reinforcing yarn ( 8 ) which takes up loops disposed parallel to the warp yarn loops in the eyelet region in order to take up the closure wire.

The object of the invention is to provide, for fabrics of the subjecttype, a reinforcement of the stitched seam having very high seam tearstrength.

This is accomplished by adding to the warp yarn loops at the stitchedseam location and the closure wire at least one reinforcing yarn whichhas loops in the vicinity of the eyelets extending parallel to the warpyarn loops for receiving the closure wire.

Further embodiments of the invention are the subject of the dependentclaims.

Through the configuration of a stitched fabric seam in accordance withthe invention the seam tear strength is decisively increased, due to theadditional connecting yarn or wire which is enmeshed in the eyeletregion either loosely or as a helical yarn. This yarn or wire canconsist of various materials, preferably of monofilaments with round orflat cross-section, e.g. polyester, PEEK, Ryton, polyamide, PCTA, metalor the like, or of mono- and multiplastics with various core yarns. Allyarns can be braided or spun, impregnated, coated, including the use ofcarbon filaments or fibers. Further inserts of thin steel wires can beused. Reinforcing yarns of the inventive kind preferaly have a thicknesswhich is equal to or smaller than the thickness of the seam loops. Theyare, for example, anchored in each case behind one or more cross machinedirection (CMD) yarns.

In a specific embodiment of the invention the seam reinforcement is soconfigured around the closure wire that one warp yarn loop of the warpyarn from one of the fabric portions and one loop of the helicalreinforcing yarn at one side of the seam connection alternates with oneturn of the helical reinforcing strip and a warp loop of the warp yarnfrom the confronting fabric portion.

In another specific embodiment of the invention, the reinforced seamconnection is so constructed that, along the length-wise axis of theclosure wire, one warp loop of the warp yarn from one of the fabricportions alternates with one turn of the reinforcing helix of thisfabric portion with a warp loop of a warp yarn from the other fabricportion and a turn of the reinforcing strip from of the other fabricportion, and so forth.

Basically, by means of the invention, there is bound in the eyeletregion of the warp yarns adjoining both sides of the stitched seam anadditional yarn either loosely or as a separate helix. This provides ahigh tensile stitched seam which substantially enhances the seam tearstrength. That is especially desirable for fabrics with low warp yarncount, because a hinge effect which that causes has a negative influenceon the tear strength. Because of the increased seam tear strength, thereexist other possibilities for applying various combinations of materialsin eyelet region to better meet the higher requirements in paper makingmachinery technology. Because such reinforcing yarns reduce the spacingbetween the eyelets of any two adjoining warp yarns, the hinge effectwhich adversely affects or damages the seam eyelets is eliminated.

In what follows, the invention is described in conjunction with thedrawing by means of an illustrative embodiment. There is shown in:

FIG. 1 a diagrammatic illustration of the principle for twointerconnected fabric sections,

FIG. 1a a diagrammatic representation of the principle corresponding toFIG. 1 with the two fabric sections shown separated from each other,

FIG. 2 a top view of the two fabric sections in the interconnectedstate,

FIG. 3 a perspective view of a fabric end with reinforcing yarn for astitched seam according to the invention,

FIG. 4 a diagrammatic representation of an embodiment of the reinforcedstitched seam according to the invention,

FIG. 5 a further embodiment of a reinforced stitched seam according tothe invention similar to the illustration of FIG. 4,

FIGS. 6, 7, 8 photographic reproductions of the embodiments of FIG. 1, 2and 3.

The fabric consists of two fabric sections 1 and 2 whose confrontingends are firmly connected to each other. The warp yarns 3, 4 of thefabric section form loops at their ends. Each second warp yarn 3 islonger at its end than the other half of the warp yarns 4, so that theterminating line in the direction of the weft yarns 5 has a meander-likeshape. Each of the protruding warp yarn loops 6 is provided with a turn7 of a helix 8, so that warp yarn loops 6 and turns 7 are located nextto each other in the transverse direction and define a common transverseaxis X, along which a connecting wire 9 is led through the loops 6 andturns 7.

The fabric section 2, which is to be connected to the fabric section 1,consists of the warp yarns 10, 11 and the weft yarns 12, with the warpyarns 10 in section 2 being again made longer than the warp yarns 11,with the terminating line again extending in meander-like shape, butlaterally displaced by a space, so that the warp yarns 3 of section 1 ofthe fabric strip and the warp yarns 10 of section 2, as well as the warpyarns 4 and the warp yarns 11 extend in a single line in the lengthwisesurface of the fabric strip. Each of warp yarn loops 13 is provided witha turn 14 so that warp yarn loops and turns are located adjacent to eachother in the transverse direction and define a common transverse axis.

The helix 8 engaging the warp yarns of fabric section 1 and the helix 15engaging the warp yarns of fabric section 2 are located coaxially nextto each other and engage the connecting wire 9 jointly on their X axis.In so doing, the helix 8 encircles the one or more warp yarns of section1 which are closest to the axis 9 and the helix 15 the one or more warpyarns of section 2 which are closest to the X axis.

Preferably, the helix 15 also encircles that weft yarn 17 which isclosest to the end of the fabric section. However, optionally,additional weft yarns adjoining and paralleling the weft yarn 17, i.e.the second, third or fourth weft yarn from the end can be encircled,i.e. enclosed by the connecting wire in order to reinforce the anchoringof the helix.

LIST OF REFERENCE NUMERALS

1 . . . first fabric section

2 . . . second fabric section

3, 4 . . . warp yarns

5 . . . weft yarns

6 . . . warp yarn loops

7 . . . warp yarn loop turns

8 . . . helix

9 . . . transverse axis

10, 11 . . . warp yarns

12 . . . weft yarns

13 . . . warp yarn loops

14 . . . warp yarn loop turns

15 . . . helix

16 . . . connecting wire

17 . . . weft yarn at the end of the fabric section

What is claimed is:
 1. A stitched seam for high-tensile woven fabricsections in which the warp yarn loops at the end of the two fabricsections which are to be connected to each other are connected at theircommon connecting line by means of a closure wire, characterized in thatthe warp yarn loops at the stitched connecting location and the closurewire are provided with at least one reinforcing yarn which has loops inthe eyelet region paralleling the warp yarn loops for receiving theclosure wire.
 2. Stitched seam according to claim 1, characterized inthat the reinforcing yarns are firmly connected to the warp yarns. 3.Stitched seam according to claim 1, characterized in that the individualreinforcing yarn is led helically around the closure wire and around atleast one of the weft yarns adjoining the closure wire along the entireseam.
 4. Stitched seam according to claim 1 characterized in that thetwo confronting sides of the fabric sections are provided withreinforcing yarns jointly surrounding the closure wire.
 5. Stitched seamaccording to claim 1, characterized in that in the axial direction ofthe closure wire there is located one warp yarn loop and one reinforcingyarn from the one fabric section and one reinforcing yarn and one warpyarn loop from the other fabric section, each surrounding the closurewire.
 6. Stitched seam according to claim 3, characterized in that thehelical reinforcing yarn is also loosely bound into the eyelet. 7.Stitched seam according to claim 1, characterized in that thereinforcing yarns are monofilament or multifilament yarns of round orflat shape and consist of polyester, PEEK, Ryton, polyamide, PCTA ormetal.
 8. Stitched seams according to claim 1, characterized in that thereinforcing yarns have inserts of thin steel wire.
 9. Stitched seamaccording to claim 1, characterized in that the reinforcing yarnssubstantially fill the space between the eyelets of the warp loops. 10.Stitched seam according to claim 1, characterized in that thereinforcing yarns are mono- or multi plastics with various core yarns.11. Stitched seam according to claim 1 wherein the woven fabric sectionsare sections of a papermaker's dryer fabric.